It is often desirable to minimize the amount of current needed to achieve comfortable loudness sensation in a cochlear implant patient. For example, by minimizing the amount of current needed to achieve comfortable loudness sensation in a cochlear implant patient, the size of a sound processor included in a cochlear implant system (i.e., the size of a battery module included in the sound processor) may be minimized.
One way to reduce the amount of current utilized by a cochlear implant system is to reduce the compliance voltage associated with a cochlear implant included in the cochlear implant system (i.e., the voltage maintained by the cochlear implant that governs a maximum amplitude of stimulation current that can be delivered by the cochlear implant). Unfortunately, loudness sensation is determined by the amount of charge delivered to individual electrodes or channels. The amount of charge delivered to individual electrodes is a function of stimulation amplitude and pulse width. Hence, a lowering the compliance voltage (and, in effect, the stimulation amplitude) may necessitate a widening of the pulse width to achieve comfortable loudness sensation. Widened pulse widths may adversely affect (i.e., decrease) the stimulation rate (i.e., the number of stimulation pulses that may be applied per given time unit). This, in turn, may lead to poor or unacceptable sound quality for some cochlear implant patients.